Elijah took twelve stones, one for each of the tribes descended from Jacob, to whom the word of the Lord had come, saying, “Your name shall be Israel.”
And the priest shall come again the seventh day, and shall look: and, behold, if the plague be spread in the walls of the house;Leviticus 14:39 KJV
With the stones he built an altar in the name of the Lord, and he dug a trench around it large enough to hold two seahs of seed.1 Kings 18:32 NIV
Then Elijah said to all the people, “Come here to me.” They came to him, and he repaired the altar of the Lord, which had been torn down.1 Kings 18:30 NIV